Composition of matter for electrolytic deposition.



[UNITED ST TES PATENT OFFICE.

'EDWARD D. KENDALL, OF YORK, N. Y.

COMPOSITION OF MATTER FOR ELECTROLYTIC DEPOSITION.

SPECIFICATION forming part of Letters Patent No. 724,107, dated March 31, 1903.

Application filed September 17, 1902. v

To all whom it may concern.-

Be it known that I, EDWARD D. KENDALL, a citizen of the United States, residing in the borough of Brooklyn, in the city and State of New York, have invented a new and useful Composition of Matter to be Used for the Electrolytic Deposition of Gold, of which the following is a specification.

The object of my invention is to obtain a solid composition of matter which by mere solution in water furnishes an electrolyte available for the electrolytic deposition of gold by means of an electric current of low electromotive force. 4

In carrying out my invention I first prepare an aurate, preferably of potassium, then dissolve this aurate in an aqueous solution of a suitable ferrocyanidfr example, potasf sium ferrocyanid-and then evaporate this liquid to dryness. To make'the potassium aurate, auric oxid may first be prepared in the usual way by precipitation with magnesia, the auric oxid to be dissolved in caustic alkali; but I have found that a more simple method yields equally satisfactory results. I usually proceed as follows: I first make gold trichlorid in the customary way by dissolving one part of goldin nitrohydrochloric acid and driving off excess of acid on the waterbath. I dissolve this gold salt in a small quantity of water and then slowly with constant stirring add this solution to, preferably, somewhat more than an equivalent quantity of potassium hydroxid,say two parts, more or less,-of potassium hydroxid dissolved in a small quantity of water. Then I add to the liquid and stir into the same a considerable quantity=-say twenty parts-of solidpow- Serial No. 123.760. (No specimens.)

dered potassiu m ferrocyanid,finally evaporating the whole todryn esson the water-bath with occasional stirring. The resulting solid product is my said composition of matter, which, with or withoutfurthcr addition of potassium ferocyanid for the purpose of increasing the electric conductivity of any otherwise very di lute solutions of the said composition and with or without the addition of common salt or any other salt for the same purpose, I generally grind to powder and put into bottles that should be well stoppered.

The proportionate quantity of water to be used in forming an electrolyte by solutio'n'of my above-described composition of matter of course may vary within wide limits. An' ounce of the solid compound ,may be dissolved in ten fluid ounces of,.water or in fifty.

What I desire to secure by Letters Patent ofthe United States is- 1. The herein-described con position of matter consisting of a suitable aur'ate and a suitableferrocyanid, substantially as described and for the purpose specified.

2. The herein-described composition of matter for pueparingan electrolyte to be used for the electrolytic deposition of gold, consisting 'name to this specification in the presence of twosubscribing witnesses.

. EDWARD D. KENDALL. Witnesses:

GUSTAV Onmorrr, FREDK. G. BIERMANN. 

